Role of intercalated Cobalt in the electronic structure of Co$_{1/3}$NbS$_2$

Abstract

Co 1/3 NbS2 is the magnetic intercalate of 2H-NbS2 where electronic itinerant and magnetic properties strongly influence each other throughout the phase diagram. Here we report the first angleresolved photoelectron spectroscopy (ARPES) study in Co 1/3 NbS2. In agreement with previous reports, the observed electronic structure seemingly resembles the one of the parent material 2H-NbS2, with the shift in Fermi energy of 0.5 eV accounting for the charge transfer of approximately two electrons from each Co ion into the NbS2 layers. However, in addition and in contrast to previous reports, we observe significant departures that cannot be explained by rigid band shift or minor deformation of bands: First, entirely unrelated to the 2H-NbS2 electronic structure, a shallow electronic band is found crossing the Fermi level near the boundary of the first Brillouin zone of the superstructure imposed by the intercalation. The evolution of the experimental spectra upon varying the incident photon energy suggests the Co origin of this band. Second, the Nb bonding band, found deeply submerged below the Fermi level at the Γ point, indicates that the interlayerhybridization is significantly amplified by intercalation, with Co magnetic ions probably acting as covalent bridges between NbS2 layers. The strong hybridization between itinerant and magnetic degrees of freedom points towards the importance of strong electronic correlations, with the interlayer coupling playing an exquisite role.

Visualizing the out-of-plane electronic dispersions in an intercalated transition metal dichalcogenide

“…After submission of this work, we found a similar photoemission work [39] that focuses on how Co intercalation doesn't fit into the rigid-band-shift picture from the pristine compound. However, here we extend this point by demonstrating a quasi-two-dimensional to three-…”